The present invention relates generally to innovations and improvements in vehicle suspensions. More particularly, the present invention relates to a new and improved vehicle suspension that does not react significantly to torsional forces produced by high-torque drivetrain such as those utilized in heavy-duty trucks and the like, yet exhibits excellent ride and handling characteristics.
For several reasons, including use of higher horsepower engines and advances in engine technology, there have been increases in the torque output of heavy-duty truck engines. Such increases have magnified the problems of driveline vibration associated with trailing arm air suspensions, which are inherently torque reactive. When increased torque is applied to the axle of a truck equipped with such a torque reactive suspension, such as during acceleration, the frame of the truck rises up and away from the drive axle. This condition is known and referred to in the art as “frame rise”.
It has been found that driveline vibration in vehicles, particularly heavy-duty trucks, is generally proportional to the severity of frame rise and wheel hop, and vice versa. Further, it has been found according to this invention that means for and methods of preventing or minimizing frame rise will result in suppressing driveline vibration and wheel hop.
Various non-reactive drive axle suspensions are known in the art. The term “non-reactive” means that the suspension does not react appreciatively to torque applied to a drive axle, particularly during acceleration and deceleration (braking).
Various roll stable suspensions are also known in the art. The term “roll stable” means that a suspension adequately resists the tendency of a vehicle to roll when negotiating sharp turns. A suspension exhibiting that feature is said to have roll stability.
Various air suspensions are also known. The term “air suspension” refers to a suspension equipped with air springs or bellows for supporting a vehicle on an axle.
Before the present invention, the various known air suspensions have not adequately managed the mobility versus stability tradeoff. Most air suspensions that are adequately roll stable do not provide adequate mobility. Conversely, most air suspensions that provide mobility do not provide sufficient roll stability. Further, such suspensions have reduced the comfort and ride characteristics of the suspension.
It is also desirable for a suspension to maintain the axle inclination angle or “pinion” angle throughout the full range of axle travel. By doing this, the axle pinion angle will more closely match the drive shaft angle and by so doing minimizes driveline vibration. The parallelogram geometry created by the beam and control rod maintains the pinion angle where a trailing arm suspension does not.
These prior art non-torque reactive suspensions are also generally heavy, translating into reduced payload capacity in commercial vehicle applications. Such suspensions are also generally expensive to manufacture in terms of increased component parts and they require lengthy installation and assembly time, which further increases their manufacturing expense. The prior art non-torque reactive suspensions also have generally low roll stability, thereby limiting use of the vehicle to certain, limited applications.
In light of the foregoing, it is desirable to design a vehicle suspension that will overcome one or more of the above-identified deficiencies of conventional non-torque reactive suspensions.
It is further desirable to design a vehicle suspension that is non-torque reactive.
It is further desirable to design a vehicle suspension that is a non-torque reactive air suspension.
It is further desirable to design a vehicle suspension that minimizes loads into the vehicle frame and its associated cross member.
It is further desirable to design a non-torque reactive suspension that exhibits excellent roll stability characteristics.
It is further desirable to design a non-torque reactive suspension that does not compromise ride and/or articulation characteristics, while providing excellent roll stability.
It is further desirable to design a vehicle suspension that minimizes the number of components required to achieve its objectives.
It is further desirable to design a vehicle suspension that can be assembled and installed in a relatively short amount of time.
It is further desirable to design a vehicle suspension that is relatively light in weight, thereby translating into increased payload capacity when used in commercial vehicle applications.
It is further desirable to provide a rear drive axle air suspension suitable for applications requiring partial off highway operation.
It is further desirable to design a vehicle suspension that is rated from 20,000 lb. to 23,000 lb. ground load per axle.
It is further desirable to design a vehicle suspension that can be used in connection with a variety of axle configurations, including single, tandem, or tridem axle configurations.
It is further desirable to design a vehicle suspension that is a non-reactive suspension developed for heavy-duty vehicles with high torque engines.
It is further desirable to design a vehicle suspension that minimizes vibration.
It is further desirable to design a vehicle suspension that improves ride quality.
It is further desirable to design a vehicle suspension that eliminates torque reactivity.
It is further desirable to design a vehicle suspension that includes various unique torque rod design configurations.
It is further desirable to provide a vehicle suspension that has an optimized parallelogram geometry.
It is further desirable to design a vehicle suspension that does not induce roll generated torque into the drive axle of a vehicle.
It is further desirable to design a vehicle suspension that includes a machine tapered joint for the connection between the longitudinally extending main beam sections and the laterally extending crossbrace.
It is further desirable to design a vehicle suspension that utilizes a D-shaped bar pin bushing for attachment to a single leg of the lower axle bracket used to connect various suspension components to the clamped drive axle housing.
It is further desirable to design a vehicle suspension that includes an axle clamp assembly bottom pad having shock and main beam bushing mounting structure for adjustment of the axle pinion angle.
It is further desirable to design a vehicle suspension that utilizes frame hanger components with intergrated main beam and control rod mounting features.
It is further desirable to design a vehicle suspension that utilizes an axle clamp assembly top pad having integrated control mounting and bump stop features.
It is further desirable to design a vehicle suspension that includes roll stiffness tuning capability.
It is further desirable to design a vehicle suspension having features that aid in the assembly of the bushing interface.
It is further desirable to design a vehicle suspension having a geometry that eliminates axle pinion angle change throughout the range of vertical axle travel.
It is further desirable to design a vehicle suspension having a geometry with links connected both above and below the axle to resist axle torsional displacements that are generated by braking and acceleration.
It is further desirable to design a vehicle suspension having a parallel geometry that reduces driveline vibration relative to typical trailing beam style suspensions common in the industry.
It is further desirable to design a vehicle suspension that incorporates one lateral control rod per axle to support lateral loads.
It is further desirable to design a vehicle suspension that has an alternative geometry replacing two longitudinal and one lateral control rod with a single V-rod configuration that forms the upper linkage in the parallelogram geometry of the suspension and supports lateral loads.
It is further desirable to design a vehicle suspension that has pivotal connections at the axle rather than rigid connections such that no torsional loads are transmitted into the axle, making the axle interface more robust than the typical rigid connection.
It is further desirable to design a vehicle suspension that eliminates the axle as an auxiliary roll-stabilizing component, yet obtains roll stability through various components of the suspension.
It is further desirable to design a vehicle suspension that prevents vehicle frame rise.
It is further desirable to design a vehicle suspension wherein the pivot for connecting other suspension components to the frame hanger is approximately aligned with the axle pivot.
These and other benefits of the preferred forms of the invention will become apparent from the following description. It will be understood, however, that an apparatus could still appropriate the invention claimed herein without accomplishing each and every one of these benefits, including those gleaned from the following description. The appended claims, not the benefits, define the subject matter of this invention. Any and all benefits are derived from the preferred forms of the invention, not necessarily the invention in general.